1. Field of the Invention
The present invention relates to a crosslinkable polymer composition. More specifically, it relates to a crosslinkable polymer composition capable of providing a polymeric material having both excellent heat resistance and excellent adhesion to metal properties.
2. Description of the Related Art
Known adhesive thermoplastic polymer compositions containing thermoplastic polymers having an alcoholic hydroxyl group in the molecule thereof and epichlorohydrin polymers have a limited heat resistance due to an unsatisfactory thermoplasticity and the presence of chlorine. In addition, practical use of the above-mentioned polymer compositions is limited because the chlorine contained in the compositions causes inherent problems from a sanitary viewpoint and pollutional problems due to the generation of poisonous gases when such compositions are incinerated, and also because the epichlorohydrin polymers are expensive.
In addition, polymer compositions comprising polyvinyl alcohols having a saponification degree of 85% or less and olefin copolymers containing 10% by weight or less of copolymerized unsaturated carboxylic acid or the anhydride thereof have been proposed in, for example, Japanses Unexamined Patent Publication (Kokai) No. 55-127450. However, these polymer compositions are heat retaining resin compositions which are developed to improve the uniform dispersibility of the heat retaining polyvinyl alcohols and olefin copolymers, and cannot be used as an adherent resin or crosslinkable resin.
Furthermore, packaging resin compositions comprising ethylene-vinyl acetate copolymers and copolymers of olefins and unsaturated carboxylic acids, unsaturated dicarboxylic acids, or unsaturated dicarboxylic acid derivatives or the derivatives thereof have been proposed in, for example, Japanese Unexamined Patent Publication (Kokai) No. 52-62382. However, although these resin compositions are suitable for use as moisture-resistant packaging materials, because they have desired gas barrier properties but are readily cut by means of a cutter, they are not suitable for use as adhesive resin compositions or crosslinkable polymer compositions.
Recently, polymeric materials having good heat resistance and also excellent adhesion to, for example, metals, are strongly desired, in particular, in the electrical and electronic equipment fields. Various polymeric materials having good adhesion to, for example, metals, at an ambient temperature are known in the art. However, polymeric materials having both excellent adhesion properties and excellent heat resistance are not known in the art. Although polyester resins and polyimide resins have been proposed as having good adhesion properties and heat resistance, polyester resins are disadvantageous in that they have high water absorption properties and large thermal expansion coefficients at a temperature of 20.degree. C. to 250.degree. C. Furthermore, polyimide resins are also disadvantageous in that they have insufficient adhesion to, for example, metals, due to the poor surface activity of the resins.